1. Field of the Invention
This invention relates to smoking articles, smoking article rods of which comprise a longitudinally extending interior zone of a constitution different from that of filler disposed outside the zone.
2. Brief Description of the Prior Art
The patents literature contains numerous references to cigarettes and cigars comprising an axial zone of a constitution different from that of tobacco filler material disposed outside the zone. According to French Patent Specification No. 1,322,254 a cigar or cigarette contains a further cigar or cigarette. The contained smoking article extends from the mouth end of the containing smoking article over about two-thirds the length of the latter. At its upstream end the contained smoking article is sealed and remains sealed until, upon approach of the coal of the containing smoking article, the seal is consumed.
There is disclosed in French Patent Specification No. 998,556 a cigarette an axial zone of which is comprised of a low quality tobacco and an annular zone of which, surrounding the axial zone, is comprised of high quality tobacco.
In U.S. Pat. No. 3,614,956 there is disclosed a cigarette comprising an axial core of absorbent material, charcoal or alumina for example, surrounded by tobacco. The absorbent material is contained in a tube of ceramic material which is, in turn, wrapped in a sleeve of smoke-impervious paper. At the mouth end, the tobacco zone is closed to smoke flow.
U.S. Pat. No. 4,219,031 discloses a cigarette comprising a self-supporting axial core of carbonised material surrounded by tobacco.
A cigarette comprising a longitudinally extending fine filament treated with a smoke-modifying agent is disclosed in United Kingdom Patent Specification No. 2 070 409 A.
Cigarettes and cigars comprising axially disposed tubes formed of tobacco leaf are disclosed in United Kingdom Patent Specification No. 232,819.
United Kingdom Patent Specification No. 1,086,443 presents a disclosure of a cigarette an axial zone of which contains no tobacco or tobacco at a low packing density.
Numerous proposals have been made for methods of making cigarettes comprising an axial zone of a first tobacco and a concentric layer of a second tobacco. Such methods are disclosed in U.S. Pat. No. 1,829,559 and UK Patent Specification Nos. 1,054,557; 1,305,900; 1,416,020; 1,475,494; 1,541,339; 2 132 068 A and 2 133 966 A.